Nozzle vane assembly



Aug- 30 1965 A. D. NICHOLS ETAL 3269702 NOZZLE VANE ASSEMBLY Filed Jan. l5. 1964 United States Patent O 3,269,702 NOZZLE VANE ASSEMBLY Arnold D. Nichols, Newington, and Emil E. Werstler,

Manchester, Conn., assignors to United Aircraft Corporation, East Hartford, Conn., a corporation of Delaware Filed Jan. 13, 1964, Ser. No. 337,407 11 Claims. (Cl. 253-78) This invention relates to a vane assembly for a turbine.

One feature of the invention is an improved vane attachment and supporting structure. Another feature is an arrangement for securely attaching each vane in position t obtain the benefit of a welded structure but to retain the advantage of individual vane removal if necessary for replacement. Another feature is an arrangement for removal of individual vanes but with each of the vanes held securely in place when assembled and during operation.

One feature of the invention is a construction of vanes and supporting structure such that the vanes serve as load-carrying members and provide a bearing supporting structure for the turbine rotor.

Other features and advantages will be apparent from the following description taken in connection with the accompanying drawing which illustrates an embodiment of the invention.

FIG. 1 is a sectional view through the turbine assembly.

FIG. 2 is a sectional View on the line 2-2 of FIG. l.

The invention is shown in connection with a free turbine arrangement in which the turbine is supplied by hot gas under pressure from a conventional gas turbine powerplant, the free turbine being located in the exhaust system of the powerplant and receiving and being powered by the exhaust gas from the powerplant. Although this is the environment in which the invention is shown, it is obvious that the invention is applicable to other turbine constructions.

The turbine shown has an annular inlet 2 made up of an outer turbine case 4 and an inner duct wall 6. The turbine case 4 may carry a heat shield 8 which, in effect, forms the outer wall of the gas path. The turbine case is connected as by bolts to an outer nozzle ring 12. The vanes 14 are individual vanes and are attached as by bolts 16 to the outer nozzle ring 12 and by bolts 18 to an inner nozzle ring 20. The latter carries an integral conical bearing support 22, the inner end of which carries a sleeve 24 to support a bearing 26 for the turbine rotor 28. The rotor includes a hub 30 attached to a rotor disc 32 on the periphery of which a row of turbine blades 34 is mounted. The conical structure 22 has bolted to it another conical structure 36 which extends forwardly of the device and carries at its forward end the inner duct wall 6. Suitable 'heat shields 38 may also be carried by the conical structure 22 to shield the bearing 26 and also to form a chamber 40 in which lubricant from the bearing may collect.

In accordance with the invention, the turbine vanes 14 are individually attached to the inner nozzle ring by the bolts 18 which extend in a radial direction through circumferential flanges 42 and 44 on each of the inner shrouds 45 integral with the vanes and through cooperating portions of the nozzle ring. The latter has spaced cylindrical surfaces 46 and 46 with which the flanges 42 and 44 are held securely in engagement when the bolts 18 are tightened.

At its outer end the outer shroud element 47 for each vane 14 is bolted securely to the outer nozzle ring 12 by the bolts 16, which, as shown, also extend in a radial direction and hold circumferentially extending flanges 48 and 50 on the shroud element against cylindrical surfaces 52 and 54, respectively, formed on the ring 12. A shoul- Patented August 30, 1966 ICC der 56 at the end ofthe surface 54 may serve tolocate the individual vanes axially of the ring during assembly. When the bolts 16 are secured tightly in position, the flanges 48 and 50 are clamped tightly against the outer nozzle ring 12 and are held securely therein.

The dimensions of the vanes and the inner and outer vane supporting rings are so selected that at steady state condition the vanes and the bolts 16 and 18 are loaded in tension and the load is carried from the outer ring 12 through the vanes and Ithrough the inner ring 20 to hold .the bearing support sleeve 24 securely in concentric relation to the outer vane ring. During transient conditions the relative expansion of the parts may be such that the vanes are stressed in compression rather than tension but the spacing of the flanges 42 and 44 which extendrespectively forwardly and rearwardly of the air flow portion of each of the vanes provides a broad base for support so that in compression the bearing supporting sleeve 24 is still maintained securely in the desired position both radially and axially with respect to the outer ring 12.

It will be further apparent that each of the vanes may be removed individually from the structure by undoing the bolts 16 and 18 which support that particular vane and moving the vane forwardly (to the left in the drawing) and then rotating the inner end of the vane forwardly when the flange 50 comes into contact with the forward portion of the outer ring 12. Obviously, the case portion 4 and duct 6 will have been removed in order to provide access to the vanes and the supporting bolts so that removal of the vane will be possible.

The above described turbine is regularly supported from a supporting structure, not shown, by supports 58 located in a rearward extension 60 on the vane supporting ring 12. In this way the ring 12 remains in position when the outer case member 4 is removed. It will be understood that the inner duct wall 6 is also moved forwardly axially in order to provide for removal of an individual vane but this is easily accomplished by removal of the bolts 62 that hold this duct wall to the conical support 36.

It is to` be understood that the invention is not limited to the specific embodiment 'herein illustrated and described, but may be used in other ways without departure from its spirit as defined by the following claims.

We claim:

1. A vane attachment including spaced concentric inner and outer supporting rings, the inner ring having axially spaced outer cylindrical surfaces and the outer ring having axially spaced inner cylindrical surfaces, a plurality of circumferentially spaced vanes extending radially between and attached to said rings, each vane having individual inner and outer shroud elements integral therewith, one for each vane, the inner shroud on each vane having axially spaced locating surfaces to engage with the outer cylindrical surfaces on the inner supporting ring, bolts extending substantially radially through said inner ring and said inner shroud for holding said shroud securely and removably against said inner ring and means for attaching the outer shroud elements releasably to the outer ring whereby each vane may be individually removed axially from the rings.

2. An attachment as in claim 1 in which the means are radial bolts for holding the outer shroud securely against radial movement -with respect to the outer supporting ring.

3. A vane attachment for the positioning and removal of individual vanes from the supporting structures, said attachment including inner and outer supporting rings, the inner ring being concentric to the outer ring and having at least two axially spaced outer cylindrical surfaces, and the outer ring having at least two axially spaced inner cylindrical surfaces, a plurality of circumferentially space-d vanes extending radially between said rings, each vane having individual inner and outer shroud elements at opposite ends thereof, one lfor each vane, and each shroud having axially spaced locating surfaces to engage with the surfaces on the adjacent supporting ring, and radially extending bolts extending through said rings and the adjacent shroud elements for holding said vanes securely against the rings in a radial direction.

4. An attachment as in claim 3 in which the two locating cylindrical surfaces on one of the rings are at different radial distances from the axis of the ring.

5. An attachment as in claim 3 in which the two spaced locating surfaces on the outer shroud element are at different distances radially from the axis of the ring.

6. An attachment as in claim 3 in which a turbine casing is provided and includes the outer ring and the inner ring has an inwardly extending flange to support a bearing.

7. A vane attachment including inner and outer supporting rings, a plurality of circumferentially spaced vanes extending radially between said rings, each vane having individual inner and outer shroud elements thereon at opposite ends for attachment of each vane separately to the inner and outer supporting rings, one of said rings having axially spaced cylindrical locating surfaces thereon for engagement with the associated shroud element, said associated shroud element having axially spaced locating surfaces for engagement with the axially spaced locating surfaces on the ring, bolts extending substantially radially through said associated shroud and the ring for holding said shroud securely against said ring in a radial direction and means for supporting the other shroud on each vane in xed axial relation to the other supporting ring whereby each vane may be individually removed axially from the rings.

8. An attachment as in claim 7 in lwhich the spaced cylindrical surfaces are on the inner ring.

9. An attachment as in claim 7 in which the axially spaced cylindrical surfaces are on the outer ring.

10. An attachment as in claim 7 in which the axially spaced cylindrical surfaces are radially offset with respect to each other.

11. An attachment as in claim 7 in which the outer ring forms a part of a turbine casing and the inner ring has an inwardly extending flange to support a bearing.

References Cited by the Examiner UNITED STATES PATENTS 2,658,719 11/1953 Johanson 253--77 2,833,463 5/1958 Morley 253-78 X 2,999,670 9/1961 Payne et al 253-78 3,026,087 3/1962 Welsh 253-78 3,042,367 7/1962 Welsh 253-77.3 X

FOREIGN PATENTS 626,485 8/1961 Canada.

1,227,668 3/ 1960 France.

MARTIN P. SCHWADRON, Primary Examiner.

JULIUS E. WEST, SAMUEL LEVINE, Examiners.

E. A. POWELL, Assistant Examiner. y 

1. A VANE ATTACHMENT INCLUDING SPACED CONCENTRIC INNER AND OUTER SUPPORTING RINGS, THE INNER RING HAVING AXIALLY SPACED OUTER CYLINDRICAL SURFACES AND THE OUTER RING HAVING AXIALLY SPACED INNER CYLINDRICAL SURFACES, A PLURALITY OF CIRCUMFERENTIALLY SPACED VANES EXTENDING RADIALLY BETWEEN AND ATTACHED TO SAID RINGS, EACH VANE HAVING INDIVIDUAL INNER AND OUTER SHROUD ELEMENTS INTEGRAL THEREWITH, ONE FOR EACH VANE, THE INNER SHROUD ON EACH VANE HAVING AXIALLY SPACED LOCATING SURFACES TO ENGAGE WITH THE OUTER CYLINDRICAL SURFACES ON THE INNER SUPPORTING RING, BOLTS EXTENDING SUBSTANTIALLY RADIALLY THROUGH SAID INNER RING AND SAID INNER SHROUD FOR HOLDING SAID SHROUD SECURELY AND REMOVABLY AGAINST SAID INNER RING AND MEANS FOR ATTACHING THE OUTER SHROUD ELEMENTS RELEASABLY TO THE OUTER RING WHEREBY EACH VANE MAY BE INDIVIDUALLY REMOVED AXIALLY FROM THE RINGS. 